we have that
points A(-3,2) and B(3,2)
we know that
The locus of points equidistant from two given points in a plane, is the straight line which is the perpendicular bisector of the segment connecting the two given points.
using a graph tool
see the attached figure
the answer is
The straight line x= 0 (which is "y-axis") is the locus of points that are equidistant from the given points